'\" et
.TH PTHREAD_SPIN_DESTROY "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\"
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
.\"
.SH NAME
pthread_spin_destroy,
pthread_spin_init
\(em destroy or initialize a spin lock object
.SH SYNOPSIS
.LP
.nf
#include <pthread.h>
.P
int pthread_spin_destroy(pthread_spinlock_t *\fIlock\fP);
int pthread_spin_init(pthread_spinlock_t *\fIlock\fP, int \fIpshared\fP);
.fi
.SH DESCRIPTION
The
\fIpthread_spin_destroy\fR()
function shall destroy the spin lock referenced by
.IR lock
and release any resources used by the lock. The effect of subsequent
use of the lock is undefined until the lock is reinitialized by another
call to
\fIpthread_spin_init\fR().
The results are undefined if
\fIpthread_spin_destroy\fR()
is called when a thread holds the lock, or if this function is called
with an uninitialized thread spin lock.
.P
The
\fIpthread_spin_init\fR()
function shall allocate any resources required to use the spin lock
referenced by
.IR lock
and initialize the lock to an unlocked state.
.P
If the Thread Process-Shared Synchronization option is supported and
the value of
.IR pshared
is PTHREAD_PROCESS_SHARED, the implementation
shall permit the spin lock to be operated upon by any thread that has
access to the memory where the spin lock is allocated, even if it is
allocated in memory that is shared by multiple processes.
.P
See
.IR "Section 2.9.9" ", " "Synchronization Object Copies and Alternative Mappings"
for further requirements.
.P
The results are undefined if
\fIpthread_spin_init\fR()
is called specifying an already initialized spin lock. The results are
undefined if a spin lock is used without first being initialized.
.P
If the
\fIpthread_spin_init\fR()
function fails, the lock is not initialized and the contents of
.IR lock
are undefined.
.P
Only the object referenced by
.IR lock
may be used for performing synchronization.
.P
The result of referring to copies of that object in calls to
\fIpthread_spin_destroy\fR(),
\fIpthread_spin_lock\fR(),
\fIpthread_spin_trylock\fR(),
or
\fIpthread_spin_unlock\fR()
is undefined.
.SH "RETURN VALUE"
Upon successful completion, these functions shall return zero;
otherwise, an error number shall be returned to indicate the error.
.SH ERRORS
The
\fIpthread_spin_init\fR()
function shall fail if:
.TP
.BR EAGAIN
The system lacks the necessary resources to initialize another spin
lock.
.TP
.BR ENOMEM
Insufficient memory exists to initialize the lock.
.P
These functions shall not return an error code of
.BR [EINTR] .
.LP
.IR "The following sections are informative."
.SH EXAMPLES
None.
.SH "APPLICATION USAGE"
None.
.SH RATIONALE
If an implementation detects that the value specified by the
.IR lock
argument to
\fIpthread_spin_destroy\fR()
does not refer to an initialized spin lock object, it is recommended
that the function should fail and report an
.BR [EINVAL] 
error.
.P
If an implementation detects that the value specified by the
.IR lock
argument to
\fIpthread_spin_destroy\fR()
or
\fIpthread_spin_init\fR()
refers to a locked spin lock object, or detects that the value specified
by the
.IR lock
argument to
\fIpthread_spin_init\fR()
refers to an already initialized spin lock object, it is recommended
that the function should fail and report an
.BR [EBUSY] 
error.
.SH "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.ad l
.IR "\fIpthread_spin_lock\fR\^(\|)",
.IR "\fIpthread_spin_unlock\fR\^(\|)"
.ad b
.P
The Base Definitions volume of POSIX.1\(hy2017,
.IR "\fB<pthread.h>\fP"
.\"
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
.PP
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
